EJB3.0 注释小结

1. @Id 显示声明属性为标识符
2. @GeneratedValue(strategy=GenerationType.IDENTITY) 表示主键是自动生成策略，strategy 有很多

?? 选择 IDENTITY 是针对 SQLSERVER 等数据的。一般该注释和 @Id 合用
3. @Entity 任何 Entity Bean 都要有次注释
4. @Table(name = "Order") 类和 Table 对应声明
5. @Column(name = "Name",nullable=false,length=32) 和 ORM 产品的 Mapping file 一样，声明数据

?? 库字段和类属性对应关系，其他选项是一样的，看看就知道了。6. @Lob?? @Basic(fetch=FetchType.LAZY) 声明字段为 Clob 或 Blob 类型，并且要 Lazy 加载。7. @PersistenceContext 往 SessionBean 中注入 EntityManager 对象8. @OneToMany(mappedBy="order",cascade = CascadeType.ALL,fetch = FetchType.LAZY)?? @OrderBy(value = "id ASC")?? 一对多声明，和 ORM 产品声明类似，一看就明白了。?? @ManyToOne(cascade=CascadeType.REFRESH,optional=false)?? @JoinColumn(name = "order_id")?? 声明为双向关联9. @Temporal(value=TemporalType.DATE) 做日期类型转换。10.@OneToOne(optional = true,mappedBy = "person")?? 一对一关联声明?? @OneToOne(optional = false,cascade = CascadeType.REFRESH)?? @JoinColumn(name = "Person_ID",referencedColumnName = "personid",unique = true)?? 声明为双向关联 11.@ManyToMany(mappedBy = "students")?? 多对多关联声明。? @ManyToMany(cascade = CascadeType.PERSIST,fetch = FetchType.LAZY)? @JoinTable(name = "Teacher_Student",??? joinColumns = {@JoinColumn(name = "Teacher_ID",referencedColumnName = "teacherid")},??? inverseJoinColumns = {@JoinColumn(name = "Student_ID",referencedColumnName =??? "studentid")})?? 多对多关联一般都有个关联表，是这样声明的！12.@TransactionAttribute(TransactionAttributeType.REQUIRED)?? 事务声明13.@ApplicationException(rollback=true) 定义回滚异常14.@PostLoad?? @PrePersist?? @PostPersist?? @PreUpdate?? @PostUpdate?? @PreRemove?? @PostRemove?? SessionBean 的生命周期的回调方法15.继承声明策略1?? @Inheritance(strategy=InheritanceType.SINGLE_TABLE)?? @DiscriminatorColumn(name="Discriminator",???? discriminatorType = DiscriminatorType.STRING,???? length=30)?? @DiscriminatorValue("Vehicle")?? 继承声明策略2?? @Inheritance(strategy=InheritanceType.JOINED)?? @Table(name="Vehicle")?? 继承声明策略3?? @Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)?? @Table(name="Vehicle")16. WebService 开发??? @WebService(name = "HelloWorld",??? targetNamespace = "http://com.jack.test",serviceName = "HelloWorldService")??? @SOAPBinding(style = SOAPBinding.Style.RPC)??? @WebMethod